Because of the high temperatures, Metra is warning its riders that they may experience 10 to 15 minute delays. Trains need to go a bit slower because of possible heat-related stress on the tracks.

The heat wave impacting Chicago will stretch across many cities in the central U.S., bringing the hottest weather of the year so far and triple-digit temperatures. It will mark the first time the city has seen a stretch of temperatures this high since 2013. In that year, July 16-19 saw highs in the 90s. A similar four-day stretch hasn't been seen since in the Chicago area.